Passing Sight Distance Calculator
Observed maneuver exposure/opposing travel plus independent clearance, not braking stopping sight distance or permission to overtake. Caller independently establishes units, regime, calibration and applicability; this does not establish design-code compliance, authenticity, operational safety, treatment efficacy or a validated forecast.
Description
A passing-distance screen combines opposing and passing speeds over a maneuver time.
A passing-distance screen combines opposing and passing speeds over a maneuver time.1
The simplified closure model does not resolve acceleration, an overtaken vehicle or a complete road-design standard. Use this tool to calculate passing Sight Distance from the supplied measurements and assumptions.
When to use Passing Sight Distance Calculator
Use this tool to calculate passing Sight Distance from the supplied measurements and assumptions. Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
How to use Passing Sight Distance Calculator and understand its results
- Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
- Enter passingVehicleSpeedMSecond, opposingVehicleSpeedMSecond, callerObservedManeuverSeconds, callerIndependentClearanceM, using the field meanings and rules below, then run the tool.
- Read relativeMotionPassingSightM. Interpret the fields using their units, signs and evidence conventions below.
- If input validation fails, correct the reported field and run again. Before applying the result, check reference scope, model assumptions and any missing evidence or placeholder values.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| passingVehicleSpeedMSecond | Passing vehicle speed m second | number | Required |
| opposingVehicleSpeedMSecond | Opposing vehicle speed m second | number | Required |
| callerObservedManeuverSeconds | Caller observed maneuver seconds | number | Required |
| callerIndependentClearanceM | Caller independent clearance m | number | Required |
Enter nonnegative passing and opposing speeds in m/s, maneuver duration in seconds and clearance in m. Add the speeds, multiply by duration and add clearance. No overtaken-vehicle trajectory, acceleration phase or design-standard minimum is supplied.
distanceM=(passingSpeed+opposingSpeed)×maneuverSeconds+clearanceM Use the exact units, boundary rules, ordering and missing-evidence conventions above.
| Output field | Meaning | Value type |
|---|---|---|
| relativeMotionPassingSightM | Relative Motion Passing Sight M; follow the units, sign, ordering and evidence convention stated above | number |
{
"input": {
"passingVehicleSpeedMSecond": 20,
"opposingVehicleSpeedMSecond": 15,
"callerObservedManeuverSeconds": 5,
"callerIndependentClearanceM": 10
},
"output": {
"relativeMotionPassingSightM": 185
}
}Limitations and assumptions
The simplified closure model does not resolve acceleration, an overtaken vehicle or a complete road-design standard. Interpretation depends on the units, sampling scope and exact model described above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse evidence arrays fail validation; the specific bounds and alignment requirements are stated above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful result reporting false, no matches or missing evidence.
Alternative or Complementary methods
Use Intersection Sight Distance Calculator for this related task: A sight-distance screen compares available distance with speed times an accepted time gap.
Use Vertical Curve Length Calculator when its separate inputs and assumptions fit the question: A grade change divided by a permitted curvature gives a conditional vertical-curve length.
References
-
Passing Sight Distance Calculator — tool.io
Similar or alternative tools
- Intersection Sight Distance Calculator
A sight-distance screen compares available distance with speed times an accepted time gap.
- Vertical Curve Length Calculator
A grade change divided by a permitted curvature gives a conditional vertical-curve length.